Sun and sea - Aug 8

Energy From the Restless SeaHeather Timmons, New York Times NEWCASTLE, England — There is more riding the waves here than surfers, thanks to a growing number of scientists, engineers and investors.

A group of entrepreneurs is harnessing the perpetual motion of the ocean and turning it into a commodity in high demand: energy. Right now, machines of various shapes and sizes are being tested off shores from the North Sea to the Pacific — one may even be coming to the East River in New York State this fall — to see how they capture waves and tides and create marine energy.

The industry is still in its infancy, but it is gaining attention, much because of the persistence of marine energy inventors, like Dean R. Corren, who have doggedly lugged their wave and tidal prototypes around the world, even during the years when money and interest dried up. Mr. Corren, trim and cerebral, is a scientist who has long advocated green energy and pushed through numerous conservation measures when he was chairman of the public energy utility for the city of Burlington, Vt.

...Britain could generate up to 20 percent of the electricity it needs from waves and tides, according to an estimate by a government-financed group here called the Carbon Trust. (3 Aug 2006)

How Australia got hot for solar powerTodd Woody, Business 2.0 Down under, they're all over alternative energy - starting with a 1,600-foot tall "solar tower" that can power a small city. -- Rattling down a red dirt road on the edge of the Australian outback, Roger Davey hits the brakes and hops out of a rented Corolla. With a sweep of his arm, he surveys his domain - 24,000 acres of emptiness stretching toward the horizon, the landscape bare but for clumps of scrubby eucalyptus trees and an occasional sheep.

It's a dead-calm antipodean winter's day, the silence of this vast ranch called Tapio Station broken only by the cry of a currawong bird. Davey, chief executive of Melbourne renewable-energy company EnviroMission, aims to break ground here early next year on the world's first commercial "solar tower" power station.

"The tower will be over there," Davey says, pointing to a spot a mile distant where a 1,600-foot structure will rise from the ocher-colored earth. Picture a 260-foot-diameter cylinder taller than the Sears Tower encircled by a two-mile-diameter transparent canopy at ground level. About 8 feet tall at the perimeter, where Davey has his feet planted, the solar collector will gradually slope up to a height of 50 to 60 feet at the tower's base.

Acting as a giant greenhouse, the solar collector will superheat the air with radiation from the sun. Hot air rises, naturally, and the tower will operate as a giant vacuum. As the air is sucked into the tower, it will produce wind to power an array of turbine generators clustered around the structure.

The result: enough clean, green electricity to power some 100,000 homes without producing a particle of pollution or a wisp of planet-warming gases. (2 Aug 2006)Technically it will take an investment of fossil fuels and wisp or two of planet-warming gases.

India is Rapidly Developing Solar EnergyBrook & Gaurav Bhagat, EcoWorld ...In terms of overall installed PV capacity, India comes fourth after Japan, the US and Germany (Indian Ministry of Non-conventional Energy Sources 2002). "India is the only country which has a separate ministry for alternative energy," Nahar said. "Government support and subsidies have been a major influence in our progress."

India is also in a good position because of the intense heat. "Arid regions receive plentiful solar radiation," he said. In computed global solar radiation of arid stations in the Indian states of Rajasthan, Gujarat and Haryana, it was found that Jaisalmer, Rajasthan, receives the maximum radiation at 6.27 kWh/m2 per day; the average daily duration of bright sunshine in Jodhpur, Rajasthan is 8.9 hours.

"Thermal solar energy can be used for water heating, cooking, drying, water distillation, refrigeration, and space heating and cooling," continued Nahar. One of the most crucial of these uses is cooking, as half the total energy consumed in developing countries is used in the domestic cooking sector; there are currently over 500,000 solar cookers in use in India, according to Nahar, including the world's largest solar cooking venue in Tirupati, which provides food for over 15,000 people each day.

Solar dryers, for dehydrating vegetables, and solar water heaters are also becoming popular. "Conventional water heaters require copper piping," Nahar said. "We have developed models using gerberized steel." These water heaters are currently used in hotels and hospitals, providing up to 100,000 litres of water per day; the cost of these is also decreasing steadily (Figure 3).

Another important area of development is that of solar stills, by which the acute draught and shortage of potable water, currently the cause of many physical disorders, can be alleviated.

Brook and Gaurav Bhagat are writers and independent filmmakers based in Jodhpur, Rajasthan, India. (8 Aug 2006)The first part of the article discusses solar energy in general.

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